The Art of Deduction
by fiesa
Summary: You have to be an emphatic mind-reader to fully understand Olivia Dunham. Either that, or your name is Rachel Dunham. OneShot.


**The Art of Deduction**

_Summary: You have to be an emphatic mind-reader to know Olivia Dunham entirely. Either that, or your name is Rachel Dunham._

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**Deductive reasoning**, also called **Deductive logic**, is reasoning which constructs or evaluates deductive arguments. In logic, an argument is deductive when its conclusion is a logical consequence of the premises.

Rachel let herself in with the key her sister had given her a year before.

It felt odd, being back again, and yet – it felt right. Olivia´s home had been a home to her and to Ella and even though they had been gone for such a long time, the surroundings still were familiar. Even thought the business that had brought her back to Boston was not without certain difficulties, she enjoyed being in the company of her elder sister once again. They always had been close, even when apart, and being the younger sister, she always had regarded Olivia as her protector. She had learned to take care of herself, of course, but old habits die hard, and Rachel loved her sister passionately. She was her sister, after all, her best friend.

"I`m back!", she called into the deserted corridor. Nobody answered, but eager voices could be heard from the kitchen. Her daughter´s voice, then Liv´s.  
"Mum!" Ella dashed towards her, followed closely by her sister. And – to her great surprise – by Peter Bishop.  
"Hey, sweetie!" Smiling widely, she bent down and swooped her daughter into her arms. "How was your day? Did Aunt Liv take good care of you?"  
Above Ella´s excited babbling, telling her something about a bakery, a carousel and very much shopping, Rachel looked at Olivia and lifted a brow in her direction. Olivia shifted uncomfortably – like a little girl caught by her parents hanging out with her boyfriend and not wanting to explain – and seemingly decided to ignore the Inquisition.  
"Hey, Rache. You had a good day?"  
"A perfect one, to be sure", she answered. "I really needed the break, it seems. It was awfully quiet without you both, though. The next time I have a day off we´ll go out together." She threw a glance around Olivia, who – somehow – had moved subconsciously, partly obscuring the tall man standing behind her.  
"Peter. Nice to meet you. How is your father?"  
"He´s fine, thanks", Olivia´s partner answered and lifted a hand. He grinned, obviously as interested as how Liv would explain his presence as she herself was. Liv, who hadn´t noticed the quiet exchange, sought help with her niece.  
"Ella. Tell your Mum what we did and how we met Peter today."  
Ella was too happy to oblige.  
"We went to the park today", she chatted away, taking Liv´s hand and pulling her into the living room. Rachel and Peter followed the pair, not without exchanging curious glances. She remembered well why Olivia had almost thrown her out of her home a year ago and while he still was as good-looking as he had been at that time, she wasn´t willing to risk her sister´s anger once again. She had gotten her message. And the way Liv threw glances at him made her see what a fragile thing she almost had destroyed. _Ha. Liv, you obviously haven´t noticed yet. _Not even after more than a year… Rachel watched her lovingly. That was just the way she was.  
Then she lifted her head. "Does it smell like dog-food here?"  
"What?" Liv´s head snapped around to meet her gaze. Defiantly. How strange. "Why the heck should it smell like dog-food? I don´t smell anything."  
"I can´t smell anything, either!" Ella nodded vigorously, her hair whipping up and down.  
"Funny." Rachel sniffed the air. "I thought…"  
"How do you know how dog-food smells like, anyway?" Her sister laughed, obviously amused. But Rachel knew her too well. She was hiding something. She was tense and seemed like… Yes, she seemed like a guilty teenager. For some reason.  
"My room-mate in college had a dog", she explained. "So I pretty well know how dog-food smells like."  
"There are a lot of things that smell quite similar", Peter offered and smirked. "Cat-food, for example." Amused, Rachel saw Olivia throw him an angry look.  
"There are other things too. Sometimes, even our food smells like dog-food."  
"You mean when you tried to cook?"  
"Sorry I burn my dinner some times, Mr. Chef-cook!", Liv snapped. Peter´s grin grew wider.  
"Well, it´s not only your dinner."  
Rachel´s eyebrows rose so high they almost were invisible under her hairline. What was going on here?  
"Be careful with what you say!" Olivia threw him a threatening glance. She seemed to have forgotten her sister was sitting next to her. "I`ll never listen to you again when you propose to have a nice dinner together just for the sake of it. And, just so you know – Astrid and Walter liked my cooking."  
"Well, that´s because Walter likes gross stuff. And Astrid is way too polite to…" A deathly look made him stop in mid-sentence.  
"Just because something smells like dog-food, this doesn´t have to mean there actually is dog-food around", she said darkly, quite obviously trying to change the topic. Rachel laughed as she saw the look on her sister´s face.  
"Come on, Liv. He´s making fun of you."  
Peter shook his head earnestly. "You take life too seriously, Liv."  
She snorted. "See who´s talking. You take it too lightly, Peter."  
Ella laughed.  
"Aunt Liv likes you", she told Peter and Rachel saw her sister blush crimson. "She only fights with people she likes. That´s what Mum says."  
"I´ll get something to drink." Rachel intended to leave Peter and Liv to themselves for a few minutes. "Ella – you help me?"  
Surprisingly, Ella clung to her skirt. "No, Mum, stay here!"  
Olivia, in equal haste, stood up and almost knocked over a pile of books lying on the table.  
"Don´t bother, Rach. I´ll get some."  
Hastily, she retreated from the room and left her younger sister staring after her suspiciously.  
"What is going on?", she asked an apparently _very_ amused Peter who was carrying a look as if he really badly was keeping himself from bursting into laughter. "What did those two do while I was gone?" She didn´t miss the secretive glance Ella through her sister´s partner.  
"I can´t say", he answered and burrowed his hands in his pockets. He sat perched on the sofa´s edge, looking as if he fit into the room perfectly. How often had he already been here? From the kitchen, a loud noise resounded, then a little yelp and a curse.  
"Aunt Liv!" Ella rushed into the kitchen.  
"Is everything alright, Liv?", Rachel called down the corridor. Her sister called back something unintelligible. She heard her and Ella bustle around and made an attempt to get up.  
"It´s fine", Peter said and held her back. "Let them finish their business there. They´ll be back in a minute."

Really, they were back within minutes, Ella carrying a bowl of cookies, Liv a tablet with glasses, water and juice. Distributing them among the people, she told Rachel: "I almost dropped the water jug. But nothing happened."  
"Is that so." It was plain to Rachel her sister was lying. But why? She threw Peter another questioning look. He grinned his maddening grin – it was this grin that made him look so damn attractive – and shrugged. Rachel shrugged, too, and agreed to drop the subject.  
"Is that dog hair on your T-Shirt, Ella?"  
"What? Where?" Her daughter spun around and almost knocked the glass from her aunt´s hand. "No! Where?"  
"I guess it´s hair from the animals we visited in the park today", Liv said and brushed it from her niece´s shirt. "They were cute, weren´t they, Ella?"  
"Yes!" Ella nodded. "Donkeys and little sheep…"  
"Lambs", Olivia corrected her. Ella smiled. "Little lambs."  
"Did the lambs bite you, Liv?"  
Olivia looked up. "Why?"  
"There are scratches on your arm. Does it hurt?"  
"What – oh, these. No, I… I just hurt myself at the fence to the enclosure. Don´t worry, the scratches aren´t deep."  
"I think I haven´t seen you with something like that since you were a teenager." Rachel sounded wistful.  
Peter grinned. "Oh, I´ve had the chance to see her much worse than that." His face clouded. "Much worse." Immediately, Rachel remembered the night when they had thought Olivia was dead and would never wake up again. She pushed away the memories hard, as, she supposed, Peter did. It cost a tremendous effort. Not only to her.  
"Well, a wire fence has teeth, too", he joked. Liv rolled her eyes. A sound came from the kitchen.

"What was that?", Rachel asked and saw her sister and daughter shrink back equally at her Inquisitor´s voice.  
"Nothing", Liv hastily said. "Maybe something has fallen from the counter…"  
"And things you keep in your kitchen fall from counters and sound like animals…"

The second Rachel had spoken the words, she could see the guilt edged openly into Olivia´s and Ella´s faces. "Oh god." She turned to them exasperated and amused at the same time. "What is it? Spill the beans. Right now."  
Ella and Liv exchanged glances. Ella shook her head.  
"Nothing, Mum. Honest."  
Rachel knew when her daughter was lying to her. "Olivia?" Her voice carried a stern tone.  
"Well…" Liv hesitated. She was a bad liar, a really bad one. Immediately, her niece threw her an angry look.  
"You said we shouldn´t tell her!"  
"But we have to tell her, eventually!"  
"No! She´ll make it go away! I want to keep it!"

"I have enough information."

Ignoring her sister and her daughter – and Peter, who had been watching the scene unfold with unhidden joy – she got up and walked briskly into the kitchen. Her eyes raked the place and encountered a brown and yellow bundle in the far corner. The heap consisted of an old blanket – and fur. Yellow fur. _Plenty of fur._

"A dog!", she exclaimed. "Of all animals in the world, you actually bring in a _dog_?"

"What´s wrong with Lea!", Ella cried, dashing past her and huddling to the bundle of bones and fur on the kitchen floor. The dog – it was a mere puppy – yelped and a bright pink tongue lashed out, plastering her daughter with saliva.  
"God!" Rachel crossed the kitchen and grabbed at Ella, who wriggled away.  
"Let go!"  
"You don´t know what this dog has got!", she exclaimed. "It probably has fleas, tape worms, and all the dirt it could find on the open street!"  
Behind Liv, Peter emerged in the kitchen door. "We took it to a vet", he said in a calming voice. "It is healthy and just had an anthelmintic therapy. It enjoyed a bath, too... The whole bathroom is floating now, but the dog is reasonably clean."  
"And fed", she added, throwing a look at the can of dog food on the counter. "I knew I smelled dog-food somewhere." She glanced at Peter. "Of all people, I wouldn´t have expected this from _you_, you know. You´re supposed to be the responsible one."  
It was Liv´s turn to receive a reproachful look. "Olivia. What´s the matter of this animal in your kitchen?"  
Liv squirmed underneath her stern glance. "We found her on the street this morning. We couldn´t just leave her there, couldn´t we? She might have died… Or worse!"  
Under her sister´s pleading look, Rachel softened. A little bit. "What will you do now?"  
"Oh…" Liv hesitated. "I think I want to keep her."  
"You _don´t_." Rachel shook her head unbelievingly. "You don´t even have time to take care of yourself, muss less than of a dog, as well. You only survive because Peter forces you to eat and sleep, right? And every plant I give you dies within four days. It´s proven statistically."  
"Mum! Mum! Can´t we keep her? Please!" Ella was dancing through the kitchen, a bundle of dog yelping and slipping behind her. It skidded on the slippery floor and crashed right into Olivia, who bend down to caress it. Peter kneeled down as well and the dog rolled over, displaying a creamy white belly, yelping and whizzing for them to scratch her. Rachel´s heart softened entirely as she watched her sister´s face. Olivia seemed… Livelier, to say the least. Her hands moved through the thick fur and she was smiling, smiling so brightly Rachel was unable to stay angry. For a few seconds, she watched all three people bend over the dog, then she sighted and crossed her arms. "And who will pay the bill for the vet, the food and all this other stuff?"

The look Ella and Olivia threw her was absolutely incredulous. Then Ella threw her arms around her. "Oh, Mum! Can we keep her?"  
"Are you sure, Rachel?", Olivia asked carefully. "I know I´m not here often, so you would have to take care of her most of the times. But I really, really would like to have a dog."  
"You can bring her to the lab", Peter suggested. "Walter would love to have company, I guess. And Gene too, probably."  
"Who is Gene?" Rachel creased her forehead. "I thought your assistant was called Astrid."  
Olivia laughed. "She is", she told her sister. "Gene is Walter´s cow."  
"A _cow_?"  
"Exactly."  
Rachel shook her head. "I knew there was something wrong with you people. Cows and dogs in labs and labs in colleges. You´re crazy."

Peter smiled at her. "Of course we are. But that´s why you like us, right?"  
"That´s it." Rachel turned around and left the kitchen. "I´m done here." Puzzled silence followed her into the corridor and greeted her when she returned, a dog leash in her hand which had been hanging over the door knob when she had entered. She grinned widely. "Anyone cares for a walk?"  
"How did you know…" Liv stopped in mid-sentence and sighted. "We´re really bad conspirators, Ella."  
"I wouldn´t trust her with a secret if I was you, Peter", Rachel said and tried to leash the dog that was running in circles and yelping away at the sight of the promised walk.  
Peter grinned at her. "I already knew that. She´s a really bad liar."  
Ella had run out and came in, wearing her shoes and her coat and ready to leave.  
"Let´s go!", she squealed. Rachel followed, the dog called Lea in front of her. Olivia and Peter followed closely.  
"Now you´ve got a dog, Liv", she said in a talkative tone, "Fancy about adding a boyfriend to your household, too?"  
She didn´t need to see Liv´s face to know blood was flooding her sister´s delicate features.  
"Stop that, Rachel", Olivia hissed. Rachel caught Peter´s grin and didn´t object as Liv snatched the leash from her hand and dashed outside, dog and girl in her trail. Rachel sighted again and looked at Peter.

"You know – it´s so easy to make her angry. I love it when she has that kind of expression."  
"I can see why." Peter´s eyes twinkled. For a second, Rachel wondered what was keeping her from simply snatching him from her sister. But then she remembered.  
"I couldn´t do that", she said conversional, pulling away from him again. "She´s my sister."  
"Right", Peter answered and looked at her seriously. "I couldn´t, either. Even though you´re like her – you´re not her."  
"Well, you´re the only one who ever chose my sister over me", she said lightly and made her way out of the door. Peter followed and pulled the door close behind him. Ella and Liv were waiting at the end of the small stairs, happily watching the dog dig out something from the neighbors' rose bushes.  
"You´d better stop her", Ella advised. Liv pulled it away and it attacked a bike´s wheel instead. Fortunately, there was no owner to be seen.  
"But I´m not stupid, either", Rachel told Peter as they followed Liv and Ella closely. "I can put two and two together. And I know – where there is smoke…"  
"Or something like that."  
"Right." A brief pause followed. Then she eyes him inquisitively. "You´ll take care of Liv for me." He showed no surprise at her sudden change of topic. Maybe it wasn´t one, either.  
"I´ll try. She takes care of herself pretty well."  
"She does. But sometimes she needs someone else."  
"She doesn´t seem to need me."  
Rachel smiled at him. "So you think."  
"I´m pretty sure I know."  
"You´re a genius. I guess you´re mostly right. But you can´t read Liv totally, whereas I _know_ her. She´s my sister. And she really loves you."

Peter was silent for a few minutes. Then he asked: "How do you know for sure?"  
It was Rachel´s turn to smile. "Oh, it´s something I deduced from various situations and occurrences. And as you have seen today – with this sister of mine, I have quite perfected the Art of Deduction."


End file.
